Electric-wave-relaying system



J. H. HAMMOND, JR. ELECTRIC WAVE RELAYING SYSTEM. APPLICATION FILED JUNEI2. I912.

2 SHEETS-SHEET WITNESSES III/VENTOR iw M Jaw man/ms Patented Aug. 19,1919.

J. H. HAMMOND, JR. ELECTRIC WAVE RELAYING SYSTEM.

APPLICATION FILED JUNE 12, 1912.

Patented Aug. 19, 1919.

2 SHEETSSHEET 2- INVENTOI? By Z M 4 2% ATTORNEYS WITNESSES "UNITEDs'ra'rns PAT OFFICE.

JOHN HAYS HAMMOND, JR, 0F GLOUCESTER, MASSACHUSETTS.

ELECTRIC-WAVE-RELAYING SYSTEM.

Specification of Letters Patent.

Patented Aug. 19, 1919.

Application filed June 12. 1912. Serial No. 703.219.

To all whom it may concern:

Be it known that I, JOHN HAYS HAM- MOND, Jr., a citizen of the UnitedStates,

residing at Gloucester, in the State of Massachusetts, have inventedcertain new and useful Improvements in Electric-Wave- Relaying" Systems,of which the following is a specification.

My invention relates to systems for the relaying of electric wavesignals, and relates more particularly to the automatic reception andtransmission of radio telegraph and telephone messages at a relaystation, and relates furthermore to methods and'apparatus for securingselectivity in such electric wave relaying systems.

.In the accompanying figures:

Figure 1 shows a transmittin station on my selective electric w-averelaylng system,

Fig. 2 shows a relay station on my system.

Fig. 3 shows a receiving station on my system, which is out of range ofthe trans- I .When telephone messages are to be sent, the

mitting stationof Fig.1, but within range of the relay station of Fig.2.

Fig. 4 shows a relay station on my system, in which part of theapparatus is of a modified form, and which has also apparatus forthelocal amplification of the received signals.

In Fig. 1 an alternating current generator G, of a frequency preferablyabove the range of audibility, energizes the field coils F of ahigh-frequency alternator H. Alternator H is inductively coupled to theantenna A by means of the coils L and L Antenna A is in circuit with acondenser transmitter N M, and interrupter I and a key K, and isgrounded at E. A resistance microphone T, in connection with the batteryB and 'electro-magnet 1), controls the diaphragm M of the'condensertransmitter.

The high-frequency alternator H produces oscillations in the antenna Aand the generator G produces amplitude variations at-a definite rate inthese oscillations, andhence in the electric waves radiated from theantenna. The interrupter I has a defi- -nite rate, Within the limits ofaudibility, and

is operated in connection with the'key K.

when telegraph signals are to' be sent;

interrupter I and the key K are kept closed, and the sound waves atmicrophone transmitter T cause vari'ationsfin the current 4 throughelectromagnet D, which latter actuother magnetic substance, and thetelephonic vibrations are impressed upon the antenna A by means of thevariations in the capacity of the condenser transmitter M N, and henceupon the electric waves radiated therefrom.

In .Fig. 2 receiving apparatus and transmitting apparatus are connectedto the same antennaA At the receiving side, antenna A is in circuit withthe inductance coil L and the variable condcnserC, and is grounded at EThe closed oscillatory cir- 'cuit L C is coupled to the open antennacircuit bymeans of the coils L and L, and both these circuits are inresonance with the high-frequency alternator H, of Fig. 1. By the actionof rectifier R and coupling coils L and L, circuit L C suppliesunidirectional current impulses to 'the circuit containing coil Lcondenser C elcctromagnet D and receiving telephone P, which circuit isin resonance with the alternatingcurrent generator G of Fig. 1.Telephone P will enable telephone messages originating at T in Fig. 1 tobe heard at the relay station. Electromagnet D actuates the condensertransmitter M N, which is in the transmitting antenna circuit A L M N EAn alternating current generator G which is of a frequency preferablyabove the limits of, audibility, energizes the field winding F ofhigh-frequency alternator H The frequency of generators G and G and ofalternators H and H should be different. Gr impresses periodic amplitudevariations on the current of H H being audibility, due to the action ofgenerator G and, in addition, vibrations are im-- pressed upon theantenna circult by means of the condenser transmitter M N whichreproduces exactly the telephone messages, originating at transmitter Tof Fig. 1, or

the telegraph signals originating at key K and interrupter I of Fig. '1.These relayed signals or messages arethus sent out with renewed powerfrom the relay station.

In Fig. 3 the receiving antenna'A 1s in circuit with inductance coil Land con-' denser C and .is grounded at E It is inductively coupled toclosed osclllatory c1 reuit LVC, and both these circults are m resonancewith alternator H of Fig. 2. The circuit L C by means of rectifier R andcoil L, supplies energy to the circuit L C P containing the coil Lcondenser C and receiving telephone P and being in res- 'onance withgenerator G of Fig. 2. All

- C, and both these circuits are in resonance with the wave frequency ofthe transmitting station. By means of the rectifier R and coupling coilL 'ciruit L C D which is in resonance with the periodic amplitudevariations of the transmitted electric'waves,

is energized. Electromagnet D actuates the magnetic diaphragm S of theresistance microphone T T is in circuit with battery B and theelectromagnets D D, D: D", D and D These electroma 'ets actuate,respectively, the magnetic diaphragms M Mfi-M M", M and M of a multiplecondenser transmitter, which transmitter is in 'thetransmi'tting antennacircuit A L L M M M M M M E An alternating current generator G of afreuency preferably above the limits of audi ili-ty, energizes the fieldwinding F of the high- V frequency alternator H :riodic amplitudevariations upon the current G impresses peof H H being inductivelyconnected with the transmitting antenna A by means of the coupling coilsL and U. The electric waves radiated from the antenn aA have periodicamplitude variations of, a fre* quency above the limits of audibility,owin to the action of the generator stand, i addition, vibrations areimpressedupon the antenna circuit, #by means of the multiple condensertransmitter M M M M M" M*,

which re roduces, with an amplified volume,

the telep one and telegraph messages. originating at thetransmittingstation. These messages are thus sent out with increasedpower fromth'e relay station. This multiple condenser 'tragsmitter hasalready been fully described in another a plioationoi mine, (Serial No.702,176, led June 7,

greater detail here.-

This multiple condenser transmitter canas the first-mentioned waves, andreceiving.

1912-), and so need, not-be described) in also be used to produce anamplification of sounds 'or. other signals at the relaystationorelsewhere. As shown, it is inductively coupled, by means of the coilL, .with the circuit containing the coilL, rectifier R loud-speakingtelephone and electromagnet D and the amplified currents induced in thislatter circuit will produce amplified sounds at Q, or will operatethrough the electroma'gnet D and relay sWitch W to actuate localmechanisms U V.

Other means may be employed for reproducing amplitude variationsforgroup frequencies in my electric waves, such as revolving', coils,high-frequency interrupters and the like, -shown and described in otherapplications of mine, other forms of microphones and othertransmittersmay beused at my transmitting and my relay stations, and variousxotherchanges and modifications, within the ability of those skilled in theart,

may be made. in the particular apparatusshown and described herein,without departing from the spirit of my invention, rovided the means setforth in the follow-- mg claims be employed.

I claim as my invention 1. A system comprising a sending station adaptedto emit electric waves having definite characteristics, a receivinstation,

and a relaying station, interpose between the sending station and thereceiving station, provlded with means for emltting waves of differentdefinite characteristics and means for receiving variable wavecharacteristics produced at the sendingstation and impressing identicalvariations on the waves emitted from said relay station,

said receiving station being turned to the wave characteristics of therelay station;

2. A system for the relaying of wireless.

signals, which comprises a sending station emitting electric waveshaving a fixed characterlstlc and a variable characteristic, a recelvmgstation, and a relay station provided and the same variablecharacteristic.

3. In a system for the relaying of wireless slgnals, a relay stationcomprising doubly selective receiving means, independent means foremitting waves having predetermined lengths andpredetermined amplitudevariations and automatically actuated means controlled by said receivingted waves.

with means for receiving and emitting .electric waves of different fixedcharacteristics means for impressing variations on theemit- 4. A methodforv relaying radio mesa sages, which consists in transmitting waveshaving*fixed characteristics and avariable characteristic from atransmitting station, receivmg sald waves at a relay station,automatically emittin vWaves from said relay station having di erentfixed characteristics from and the same variable characteristic thelast-mentioned waves-at a receiving station. v

5. In a system (for the relaying of radio messages, a relay stationcomprismg means for receiving electric vwaves having predeterminedcharacteristics, independent means for emittin electric Waves havindifferent predetermined characteristics, an means actuated by thereceived waves for impressing variations on the emitted waves.

6. A relay station for radio telephony,

; comprising means for receiving electric waves having fixedcharacteristics and a variable characteristic, means for emitting waveshaving difi'erent fixed characteristics,

and automatic means for impressing the variable characteristic of thereceived waves upon the emitted waves. 7

7. A relay station for radio signals, comprising means for receivingtuned electric waves with periodic amplitude variations, means foramplifyin the received signals,

means for transmitting diiferently tuned electric waves with differentperiodic amplitude variations, means for impressing the amplifiedsignals upon the last-mentioned waves, and means for receiving thesignals locally .in an amplified form.

8. A relay station for radio telephony, comprising selective means forreceiving electric Waves having telephonic variations, selective meansfor emitting electric waves, automatic means for amplifying thetelephonic variations and impressing them upon the emitted waves, andmeans for amplifying the received telephone mes sages.

9. A method of relaying in radio telephony which consists intransmitting 'Waves having a plurality of characteristics, im-

' ,pressing telephonic variations upon said waves, receiving said wavesat a relay station, automatically emitting waves from said relay stationhavin different characteristics from the first-mentioned Waves but thesame telephonic variations, and receiving the lastmentioned waves at areceiving station.

10. The combination with transmission means including means forgenerating electrical oscillations of a predetermined frequency, meansfor simultaneously impress ing regular eriodic variations of aredetermined requei cyand irregular, undulations corresponding to soundwaves upon said oscillations of a relay including receiving meanscomprising responsive means in resonance with said oscillations,responsive means controlled by said first mentioned responsive means andin resonance with said periodic variations, means for generatingelectrical oscillations of a predetermined frequency, means for.impressing regular periodic variations of a periodic variations, meansfor sponsive means and in resonance with said eneratin electricaloscillations of a re etermine frequency diflei'ent from said firstmentioned frequency, means for impressing regular periodic variations ofa predetermlnec'l frequency different from said second mentionedfrequency upon said last mentioned oscillations, and means controlled bysaid second mentioned responsive means for impressing undulationscorresponding to said sound waves upon said last mentioned oscillations.

12. The combination with transmission means including means forenerating electrical oscillations of a pre etermined frequency, meansfor simultaneously impress-f ing regular periodic amplitude variationsof a predetermined frequency and irregular undulations corresponding tosound waves upon said oscillations of a relay including receiving meanscomprising. responsive means in resonance with said oscillations,responsive means controlled by said first mentioned responsive means andin resonance with said periodic variations, means for generatingelectrical oscillations of a predetermined frequency, means forimpressing regular periodic amplitude variations of a predetermined.frequency upon said last mentioned oscillations, and means controlled bysaid second mentioned responsive means for impressing undulationscorresponding to said sound waves upon said last mentioned oscillations.

'This specification si ed and witnessed this 22nd day of May, I D 1912.

JOHN HAYS HAMMOND, JR.-

Witnessesi MABEL J. COOPER, OLIVE B. Knee.

